Description
Corn stunt re-emerged in 2024 across several U.S. corn-producing regions, including Texas, Oklahoma, Missouri, and Kansas, where significant yield losses were reported. In the U.S., the disease is known to be caused by a complex of pathogens, which includes the corn stunt spiroplasma (Spiroplasma kunkelii), maize bushy stunt phytoplasma (‘Candidatus Phytoplasma asteris’ subgroup 16SrI-B), and maize rayado fino virus. These pathogens are transmitted by the corn leafhopper, Dalbulus maidis, an insect vector that acquires pathogens while feeding on infected corn plants and later transmits them to healthy plants. Symptoms of corn stunt vary with hybrid susceptibility, environmental conditions, and the crop growth stage at the time of infection. Common field symptoms include chlorotic striping along leaf veins, reddening or purpling of leaves and midribs, stunting, shortened internodes, excessive tillering, reduced ear development, and loosely attached kernels. Symptoms are typically more severe when infection occurs during early vegetative stages. Because symptoms can resemble nutrient deficiencies, herbicide injury, or other diseases, accurate diagnosis should combine field observations, detection of corn leafhopper populations, and laboratory confirmation using molecular assays. Since no curative treatments are available for infected plants, management should focus on preventing early infections and reducing vector pressure. Recommended practices include eliminating volunteer corn and grass weeds that can serve as reservoirs for the insect vector, planting corn early to avoid peak corn leafhopper activity, and using insecticides to manage the insect’s population. An integrated management approach is essential for reducing the spread of disease and minimizing yield losses.
